Banquo resists the temptations of evil offered by the Supernatural appeasing to a contemporary audience,
which widely believed that the devil existed on earth and walked amongst humans trying to tempt them.
Witches = symbol of temptation to sin that Banquo, as a moral superior, is able to resist.
• When Banquo finds that the prophecy is coming true he responds with "what, can the devil speak true".
implies he views them as agents of the devil
supports James l's view in Daemonologie that witches are controlled by the devil.